When I lived in AZ, I got my talon converted over to a refrigerant called Freeze 12. The only thing they had to change was the fitting on the AC line, and then they removed the old stuff and put in the new. And the Freeze 12 is supposed to be real cheap. I haven't seen it up here though, so not sure how I'm going to recharge it when that time comes.
EDIT:
http://www.freeze-12.com/
http://www.sherco-auto.com/fr4012.htm
There's a link to what I am converted to. Supposed to actually be colder then R-134a, and a fairly easy conversion for older R-12 systems like ours.